export class Base64 {
    _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

    _utf8_encode(string: String) {
        let utftext = "", c, n;
        string = string.replace(/\r\n/g, "\n");
        for (n = 0; n < string.length; n++) {
            c = string.charCodeAt(n);
            if (c < 128) {
                utftext += String.fromCharCode(c);
            } else if ((c > 127) && (c < 2048)) {
                utftext += String.fromCharCode((c >> 6) | 192);
                utftext += String.fromCharCode((c & 63) | 128);

            } else {
                utftext += String.fromCharCode((c >> 12) | 224);
                utftext += String.fromCharCode(((c >> 6) & 63) | 128);
                utftext += String.fromCharCode((c & 63) | 128);
            }
        }
        return utftext;
    }
    _utf8_decode(utftext) {
        let string = "", i = 0, c = 0, c1 = 0, c2 = 0;
        while (i < utftext.length) {
            c = utftext.charCodeAt(i);
            if (c < 128) {
                string += String.fromCharCode(c);
                i++;
            } else if ((c > 191) && (c < 224)) {
                c1 = utftext.charCodeAt(i + 1);
                string += String.fromCharCode(((c & 31) << 6) | (c1 & 63));
                i += 2;
            } else {
                c1 = utftext.charCodeAt(i + 1);
                c2 = utftext.charCodeAt(i + 2);
                string += String.fromCharCode(((c & 15) << 12) | ((c1 & 63) << 6) | (c2 & 63));
                i += 3;
            }
        }
        return string;
    }
    _hexEncode(input) {
        let output = '';
        for (let i = 0; i < input.length; i++) {
            output += input.charCodeAt(i).toString(16);
        }
        return output;
    }
    _hexDecode(input) {
        let output = '';
        if (input.length % 2 > 0) {
            input = '0' + input;
        }
        for (let i = 0; i < input.length; i = i + 2) {
            output += String.fromCharCode(parseInt(input.charAt(i) + input.charAt(i + 1), 16));
        }
        return output;
    }
    encode(input) {
        let output = "", chr1, chr2, chr3, enc1, enc2, enc3, enc4, i = 0;
        input = this._utf8_encode(input);
        while (i < input.length) {
            chr1 = input.charCodeAt(i++);
            chr2 = input.charCodeAt(i++);
            chr3 = input.charCodeAt(i++);
            enc1 = chr1 >> 2;
            enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
            enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
            enc4 = chr3 & 63;
            if (isNaN(chr2)) {
                enc3 = enc4 = 64;
            } else if (isNaN(chr3)) {
                enc4 = 64;
            }
            output += this._keyStr.charAt(enc1);
            output += this._keyStr.charAt(enc2);
            output += this._keyStr.charAt(enc3);
            output += this._keyStr.charAt(enc4);
        }
        return output;
    }
    decode(input) {
        let output = "", chr1, chr2, chr3, enc1, enc2, enc3, enc4, i = 0;
        if (input != undefined) {
            input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
            while (i < input.length) {
                enc1 = this._keyStr.indexOf(input.charAt(i++));
                enc2 = this._keyStr.indexOf(input.charAt(i++));
                enc3 = this._keyStr.indexOf(input.charAt(i++));
                enc4 = this._keyStr.indexOf(input.charAt(i++));
                chr1 = (enc1 << 2) | (enc2 >> 4);
                chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
                chr3 = ((enc3 & 3) << 6) | enc4;
                output += String.fromCharCode(chr1);
                if (enc3 !== 64) {
                    output += String.fromCharCode(chr2);
                }
                if (enc4 !== 64) {
                    output += String.fromCharCode(chr3);
                }
            }
        }
        return this._utf8_decode(output);
    }

    decodeToHex(input) {
        return this._hexEncode(this.decode(input));
    }
    encodeFromHex(input) {
        return this.encode(this._hexDecode(input));
    }
}